import { content } from "@deadhead/content";
import type { PlayerState, Ship } from "@deadhead/schema";
import { checkRoute, effectiveStats } from "@deadhead/sim";

export interface OriginReach {
  originId: string;
  /** Purchasable models in range from there, then the player's upgraded ships there. */
  reachers: string[];
}

/**
 * Where the player could fly from: discovered locations with one of their HQs
 * or idle ships (CR-012). Earth when there are none yet (the tutorial).
 */
export function playerOrigins(state: Pick<PlayerState, "bays" | "ships" | "locations">): string[] {
  const used = new Set([
    ...state.bays.map((b) => b.locationId),
    ...state.ships.flatMap((s) => (s.locationId ? [s.locationId] : [])),
  ]);
  const origins = state.locations.filter((l) => l.discovered && used.has(l.id)).map((l) => l.id);
  return origins.length > 0 ? origins : ["earth"];
}

/**
 * Who can fly to `locationId` right now, per origin (Steps 10A.16, 10L.8):
 * purchasable models whose range from that origin covers the leg (the sim's
 * route check, with the origin's range factor), and the player's ships at that
 * origin that get there only thanks to their upgrades (CR-009). Origins with
 * nobody are left out.
 */
export function reachersByOrigin(
  state: Pick<PlayerState, "bays" | "ships" | "locations">,
  locationId: string,
): OriginReach[] {
  const target = content.location(locationId);
  if (!target) return [];
  return playerOrigins(state)
    .filter((id) => id !== locationId)
    .map((originId) => {
      const origin = content.location(originId)!;
      const reaches = (stats: Parameters<typeof checkRoute>[0]) =>
        checkRoute(stats, origin, target, content.config).ok;
      const models = content.purchasableShipModels.filter(reaches).map((m) => m.name);
      const upgraded = state.ships
        .filter((ship: Ship) => {
          const model = content.shipModel(ship.modelId);
          if (ship.locationId !== originId || !model?.purchasable) return false;
          if (Object.keys(ship.upgrades).length === 0 || reaches(model)) return false;
          return reaches(effectiveStats(model, ship.upgrades, content));
        })
        .map((ship) => `your ${ship.name} (upgraded)`);
      return { originId, reachers: [...models, ...upgraded] };
    })
    .filter((o) => o.reachers.length > 0);
}